Beverage preparation machines

ABSTRACT

Method of preparing beverages using a beverage preparation machines and in particular a beverage preparation machine of the type which uses pre-packaged containers of beverage ingredients. The method includes controlling the volume of air resident in at least a part of a delivery system of the machine to produce predetermined characteristics in a prepared beverage.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a U.S. national phase application of InternationalApplication No. PCT/GB2010/000551, filed Mar. 24, 2010, which claimsbenefit from Great Britain Application No. 0907612.6, filed May 1, 2009,both of which are hereby incorporated herein by reference in theirentirety.

FIELD

The present invention relates to improvements in beverage preparationmachines and in particular to a beverage preparation machine of the typewhich uses pre-packaged containers of beverage ingredients.

BACKGROUND

Coffee houses have been a part of the “coffee culture” since the 17^(th)century. Throughout the years methods of making coffee have been refinedand skilled people trained to produce the best coffee beverages. Thefirst coffee machines were developed in the early 1800s and an automaticespresso machine was invented in the 1930s. The automation of the coffeemaking process has, in turn, lead to a rapid growth, particularly in thelast ten years, in the number of coffee houses/shops with morespecialist drinks, such as espresso and cappuccino, being in highdemand. These types of beverages have historically been regarded asluxury items because of the need for expensive, complex machines capableof producing the high pressures necessary for making them, which had tobe properly operated and maintained by a trained barista to produce goodquality. Coffee aficionados agree that an espresso can be spoiled by abadly trained operator despite the use of a good quality machine andgood quality coffee. This trend, however, has not only lead to anincreased demand from consumers for luxury top quality beverages, butalso a desire for a greater variety of speciality beverages, and theability to make such beverages in the comfort of one's own home.

Although there is no agreed technical definition, it is generallyunderstood that, compared to drip coffee, barista quality espresso has athicker consistency, due to a higher amount of dissolved solids and fineoil droplets suspended throughout the drink. It has a smooth, yet thick,dark reddish brown crema making up 10 to 30% of the beverage. The cremais a polyphasic emulsion of air and the oils, proteins and sugarsextracted from the coffee which is produced at a high pressure,traditionally in the region of 9 to 10 bar. The higher pressuresincrease the rate of coffee wetting and improve extraction as well asbeing responsible for the development of the crema.

It is acknowledged, by discerning espresso drinkers, that espressoproduced using water which is cooler than the optimum temperature tastessour and that produced with water which is hotter than this temperaturetastes bitter. The optimum temperature is claimed to be between 92 and96° C. Other factors which affect the quality of the espresso includethe roasting and age of the coffee beans, the grind size, the compactionof the grinds prior to brewing, and the brew time. The “best” espressois achieved by balancing these key elements of the brewing process.

Domestic coffee machines have also developed significantly since thefirst filter machines were invented in the 1960s and coffee machines arenow essential pieces of kitchen equipment in many households. Some suchmachines dispense individual servings of a beverage directly into adrinking receptacle, and derive the beverage from a bulk supply ofbeverage ingredients or from individual packages of beverage ingredientssuch as pods, pads or cartridges. In the following specification suchpackages will be referenced by the general term cartridges. Machineswhich use such cartridges eliminate the need for cleaning and can enablethe user to make a selection of beverages. An example of one type ofsuch cartridge is described in EP-A-1440903. The beverages are formedfrom brewing, mixing, dissolving or suspending the beverage ingredientsin water. For example, for coffee beverages, heated water is forcedthrough the cartridges to form the extracted solution. The use ofcartridges in such machines has become increasingly popular due to theirconvenience and the quality of the beverage produced.

An example of a machine for preparing beverages using this type ofcartridge is described in EP-A-1440644. This type of machine provided,inter alia, an improvement over the prior art known at the time in thatit operated at a lower pressure than the previously known machines,which were designed for the commercial or industrial markets rather thanthe domestic market. Hence it was more suitable for the domestic marketin terms of cost, reliability and performance. However, the problem thatfaces systems that operate at a lower pressure is that they aregenerally not capable of producing barista quality espressos, whichrequire a significantly higher pressure.

With the change in consumer trends, however, there is a desire fordomestic machines which are capable of producing barista qualityespresso and a range of other beverages, for which no training isnecessary, which are affordable and which require little or no cleaning.

Some machines available on the market claim to produce higher qualitybeverages but for various reasons, they are comparatively expensivemachines. Examples of such machines are the Gaggia L'Amante™, the GaggiaEvolution™, the Nespresso Delonghi Latissimma 660™, and the KrupsXN2101™.

Most of these machines require specially designed cartridges ofincreased complexity and a particular specification of materials to copewith the high pressures involved in the brewing process for espresso.These cartridges generally incorporate filters and the process uses thegeometry of the cartridge to enable the desired quality of the beverageto be produced under high pressure. This constrains the use of thecartridges in the machine for which it is designed.

SUMMARY

It is, however, desirous to provide an improved beverage preparationmachine capable of making a selection of beverages, including a premiumquality espresso as well as non-espresso beverages, preferably usingpre-packed beverage cartridges. The machine may also be a bulk brewer orother non-cartridge machine

It is also desirous to provide a machine which is backwardly compatiblewith existing cartridges, such as those described in EP-A-1440903, whichare used in existing low pressure beverage preparation machines.

Accordingly, the present invention provides a method of preparingbeverages using a beverage preparation machine for preparing beveragesfrom one or more beverage ingredients, characterised by controlling thevolume of gas in at least a part of a delivery system of the machine toproduce predetermined characteristics in a prepared beverage.

The volume of gas is preferably actively controlled by increasing thevolume to increase the gas:liquid ratio in the beverage produced,decreasing the volume to decrease the gas:liquid ratio or maintainingthe volume.

Preferably the volume of gas in the delivery system is controlled byinducting additional gas into the delivery system, venting gas from thedelivery system and/or purging the delivery system.

The method preferably further comprises the step of measuring the actualvolume of gas resident in the delivery system.

An actual volume of gas resident in the delivery system may becalculated from stored parameters relating to a volume of gas remainingin the delivery system after a last operation of the machine.

Control of the volume of gas is preferably effected on a beverage bybeverage basis and is preferably effected automatically according to thetype of beverage being produced.

Alternatively the control of the volume of gas is effected manually.

The volume of gas upstream and/or downstream of the beverage ingredientsmay be controlled.

Preferably the volume of gas is controlled by selectively opening and/orclosing valve means in the delivery system prior to and/or duringbeverage preparation.

The invention also provides a beverage preparation machine for preparinga beverage from one or more beverage ingredients, characterised by theprovision of means for controlling the volume of gas in at least a partof a delivery system of the machine to produce predeterminedcharacteristics in a prepared beverage.

The machine preferably comprises means for determining the actual volumeof gas resident in the delivery system.

The means for determining the actual volume of gas resident in thedelivery system may comprise means for calculating the actual volumefrom stored parameters relating to a volume of gas remaining in thedelivery system after a last operation of the machine.

Preferably the stored parameters comprise a basic volume parameterstored in the control means, said basic volume being the actual volumeof gas which resides in the delivery system of an unused machine or amachine after a purging cycle has been run.

The stored parameters may comprise parameters relating to the actualvolume of gas remaining in the delivery system after each type ofbeverage which the machine is programmed to prepare.

The means for determining the actual volume of gas resident in thedelivery system preferably comprise means for measuring the actualvolume of gas in the delivery system.

Parameters relating to predetermined volumes of gas required to bepresent in the delivery system for preparing a predetermined range ofbeverages are preferably stored in the control means, said control meansbeing programmed to calculate the difference between the predeterminedvolume required for a beverage in preparation and the actual volumepresent.

The means for controlling the actual volume of gas may comprise valveand/or purge means for venting gas and/or pump means for injectingadditional gas into the delivery system.

Preferably the valve means comprise an outlet valve downstream and/or avalve upstream of the beverage ingredients.

Operation of the valve means is preferably controlled relative to thebeverage preparation cycle to vary the actual volume of gas present inthe delivery system.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiments of the present invention will now be described, byway of example only, with reference to the accompanying drawings inwhich:

FIG. 1 is a front perspective view of a prior art beverage preparationmachine with the cartridge head in a closed position;

FIG. 2 is a front perspective view of the machine of FIG. 1 with thecartridge head in an open position;

FIG. 3 is a rear elevation of the machine of FIG. 1 with some partsomitted for clarity;

FIG. 4 is a front perspective view of a cartridge head of the machine ofFIG. 1 with some parts omitted for clarity;

FIG. 5 is another front perspective view of the cartridge head of FIG.4, with some parts omitted for clarity;

FIG. 6 is a cross-sectional view of the cartridge head of FIG. 4 in aclosed position accommodating a version of a beverage cartridge;

FIG. 7 is a cross-sectional side elevation of the cartridge head of FIG.4 in an open position accommodating the beverage cartridge;

FIG. 7a is a plan view of a rubber seal for the cartridge head of FIG.4;

FIG. 8 is a schematic showing the various component parts of the machineof FIG. 1 incorporating a new variable outlet valve;

FIG. 9 is a section of schematic of an outflow from the cartridge headincorporating the variable outlet valve of FIG. 8;

FIGS. 10-12 are cross-sectional front elevations of one embodiment ofthe variable valve in the outflow of FIG. 9 showing it's closed, openand restricted positions respectively;

FIGS. 13a and 13b are cross-sectional end elevations of an alternativevariable outlet valve used in the outflow of FIG. 9 in its open andclosed position respectively;

FIGS. 14 and 15 are cross-sectional side elevations of the valve ofFIGS. 13a and 13 b;

FIG. 16a is a side elevation of a beverage receptacle containing acoffee beverage having a large volume of crema produced using animproved gas management system;

FIG. 16b is a chart showing the brew parameters used in producing thebeverage illustrated in FIG. 16 a;

FIG. 17a is a side elevation of a beverage receptacle containing acoffee beverage having a small volume of crema produced using theimproved gas management system;

FIG. 17b is a chart showing the brew parameters used in producing thebeverage illustrated in FIG. 17 a;

FIG. 18 is a plan view of a beverage cartridge suitable for use in thebeverage preparation machine of FIG. 1;

FIG. 19 is cross-sectional side elevation of an outer member of thecartridge of FIG. 18;

FIG. 20 is a cross-sectional side elevation of a detail of the outermember of FIG. 19 showing an inwardly directed cylindrical extension;

FIG. 21 is a cross-sectional side elevation of a detail of the outermember of FIG. 19 showing a slot;

FIG. 22 is a perspective view from above of the outer member of FIG. 19;

FIG. 23 is a perspective view from above of the outer member of FIG. 19in an inverted orientation;

FIG. 24 is a plan view from above of the outer member of FIG. 19;

FIG. 25 is a cross-sectional drawing of an inner member of thecartridge;

FIG. 25a is a cross-sectional drawing of a detail of the inner member ofFIG. 25 showing an aperture;

FIG. 26 is a perspective view from above of the inner member of FIG. 25;

FIG. 27 is a perspective view from above of the inner member of FIG. 25in an inverted orientation;

FIG. 28 is another cross-sectional drawing of the inner member of FIG.25;

FIG. 28a is a cross-sectional drawing of another detail of the innermember of FIG. 25 showing an air inlet;

FIG. 29 is a cross-sectional side elevation of the cartridge in anassembled condition; and

FIG. 30 is a cross-sectional side elevation of another version ofcartridge.

FIG. 31 is a graph of a digital image analysis showing a comparison ofthe crema characteristics produced by the present beverage preparationmachine utilising the gas management system and two prior art machineswithout such gas management system.

DETAILED DESCRIPTION

In order to cater for the desired wide selection of good qualitybeverage types, having different characteristics, the present inventioninvolves one or more significant improvements to known beveragepreparation machines. These improvements enable sufficiently highpressures to be generated and maintained for the production of goodquality espressos, and the pressure to be varied in a manner which isinvisible to the user and requires no manual intervention. Furthermorethey enable the crema to be improved in a way not previously possible.

These improvements, which will be described in more detail below,include:—

1. providing a variable geometry valve downstream of the beveragecartridge to enable the beverage preparation machine to operate at arange of pressures; and

2. providing greater control over the end appearance of the dispensedbeverage, in particular beverages with crema, by controlling the volumeof gas passed through the beverage ingredients.

The aforementioned improvements will be described with reference to aknown beverage preparation machine 10 which is illustrated in FIGS. 1 to7 of the accompanying drawings. It should be noted, however, that theimprovements find application in a wide range of beverage preparationmachines capable of using a wide range of cartridges which, as notedabove, include pods, pads, rigid and semi-rigid cartridges.

The beverage preparation machine 10 of FIGS. 1 to 3 generally comprisesa housing 11, a tank 12, a water heater 13, a control processor (notshown), a user interface 16 and a cartridge head 17. The cartridge head17 in turn generally comprises a cartridge holder 18 for holding, inuse, a beverage cartridge 100 and cartridge recognition means 20. Thecartridge head 17 further comprises inlet and outlet piercers 21,22 forforming in the beverage cartridge 100, in use, an inlet 107 for liquidto enter the cartridge 100 and an outlet 108 for the prepared beverageto exit the beverage cartridge 100.

Although water is likely to be the most common liquid used in preparingbeverages such as coffee, the machine 10 is also capable of handlingother liquids, such as milk or milk preparations, for mixing with thebeverage ingredients 200. Any references herein to water should also betaken to include any form of liquid used in preparing beverages.

The housing 11 is preferably made in whole or in part from a suitableplastics material or metal. The housing 11 preferably comprises aclam-shell design having a front half 25 and a rear half 26 which allowaccess during assembly for fitting of the machine 10 components.

The front half 25 of the housing 11 defines a dispensing station 27where dispensation of the beverage takes place, which includes acupstand 23 with a drip tray located beneath. The machine user interface16 is also located on the front of the housing 11 and comprises aplurality of control switches, for example, a start/stop button 28, anda number of status indicators 29-32. The status indicators 29-32 arepreferably light emitting diodes (LED) which, for example, indicatereadiness of the machine 10, whether an error has occurred in themachine 10 operation, and the mode of operation of the machine 10. TheLEDs 29-32 may be controlled to illuminate at a constant intensity, toflash intermittently, or both depending on the status of the machine 10.The LEDs 29-32 may have a variety of colours including green, red andyellow. The start/stop button 28 controls commencement of the dispensecycle and is preferably a manually operated push-button, switch orsimilar.

The tank 12 is located to the rear of the housing 11 and is preferablyincorporated in, or connected to, the rear half 26 of the housing 11.The tank 12 has an inlet for filling the tank 12 with water, or otherliquid, which is closed off when the tank 12 is in position in themachine 10. An outlet is provided towards a lower end of the tank 12which communicates with the pump 14. The tank 12 may be made from atransparent or translucent material to allow a consumer to view thequantity of water remaining in the tank 12. Alternatively, the tank 12may be made from an opaque material but have provided a viewing windowtherein. In addition, or in place of the above, the tank 12 may beprovided with a low level sensor which prevents operation of the pump 14and optionally triggers a warning indicator, such as an LED, when theliquid level in the tank descends to a preselected level. The tank 12preferably has an internal capacity of approximately 1.5 liters.

The pump 14 is operatively connected between the tank 12 and the waterheater 13, as shown schematically in FIG. 8, and is controlled by thecontrol processor. A suitable pump provides a flow rate of 900 ml/min ofwater at a pressure of 6 bar. The flow rate of water through the machine10 can be controlled by the control processor to be a percentage of themaximum flow rate of the pump 14 by cycle chopping the electrical supplyto the pump. Preferably the pump can be driven at any of 10%, 20%, 30%,40%, 50%, 60%, 70%, 80%, 90% or 100% of the maximum rated flow rate. Theaccuracy of the volume of water pumped is preferably + or −5% leading toa + or −5% accuracy in the final volume of the dispensed beverage. Avolumetric flow sensor (not shown) is preferably provided in the flowline either upstream or downstream of the pump 14. Preferably, thevolumetric flow sensor is a rotary sensor.

The heater 13 is located in the interior of the housing 11. One suitableheater 13 has a power rating of 1550 W and is able to heat waterreceived from the water pump 14 from a starting temperature ofapproximately 20° C. to a nominal operating temperature of around 85° C.in under 1 minute. Preferably the dwell time between the end of onedispense cycle and the heater 13 being able to commence a subsequentdispense cycle is less than 10 seconds. The heater maintains theselected temperature to within + or −2° C. during the dispense cycle.The water for the dispense cycle is delivered to the cartridge head 17at a predetermined temperature. The heater 13 is able to quickly adjustthe delivery temperature to the required temperature, generally between80° C. and 98° C. and possibly higher from the incoming watertemperature. Where desired, the machine 10 can incorporate a steampurge. The preferred means of generating the steam purge is to utilise awater heater 13 in the form of a flash (also known as an instantaneousor flow) heater. Typically such flash heaters comprise a tube throughwhich the water passes wherein the tube is heated by one or moreresistive elements. The flash heater can be used not only for heatingwater for forming beverages but also, at higher power settings, forgenerating a steam purge by boiling off water remaining with the flashheater tube after the beverage has been formed. An advantage of flashheaters is that there is no significant delay whilst water in a boilerheats up. Flash heaters heat water on demand and switch off immediatelyafter each brewing cycle and are therefore very energy efficient.

Water output from the heater 13 is fed via a suitable delivery system tothe cartridge head 17 and cartridge 100 by means of a valve. If thepressure of the water flow is acceptable, the water is passed to thecartridge 100. If the pressure is below or above predetermined limitsthen the water is diverted by means of the valve to a waste recoveryreceptacle.

The delivery system comprises conduits which connect the tank 12, thewater pump 14, the water heater 13 and the cartridge head 17 (as shownin FIG. 8) to transport the water from the tank 12 to the cartridge 100.

The cartridge holder 18 is designed to be capable of handling theopening forces generated by the pressure inside the cartridges 100,which is around 250 kg for espresso beverages. During operation of themachine 10 the cartridges 100 attempt to expand, but the integrity ofthe cartridges 100 must be maintained. In addition the user must not beable to open the holder 18 whilst the system is pressurised and suitablelocking mechanisms are provided to achieve this.

One suitable design of cartridge head 17, as described inWO-A-2006/014936, is shown in FIGS. 4 to 7. The cartridge holder 18 ofthe cartridge head 17 comprises a fixed lower part 43, a rotatable upperpart 44 and a pivotable cartridge mount 45 positioned between the fixedlower part 43 and the rotatable upper part 44. The upper part 44, lowerpart 43 and cartridge mount 45 are rotated about a common hinge axis 46.FIGS. 4 to 7 show the holder 18 with some components of the machine 10omitted for clarity.

The rotatable upper part 44 and pivotable cartridge mount 45 are movedrelative to the fixed lower part 43 by means of a clamping mechanism.The clamping mechanism comprises a clamping lever having first andsecond members or parts 47 and 48. The first part 47 of the clampinglever comprises a U-shaped arm which is pivotably mounted to the upperpart 44 at two first pivot points 48, one on each side of the holder 18.

The second part of the clamping lever comprises two over-centre arms 49,one on each side of the holder 18 which are each pivotably mounted tothe upper part 44 at a second pivot point 50 located on the hinge axis46 coupling the upper part 44 to the fixed lower part 43. Eachover-centre arm 49 is a reciprocal member comprising a cylinder 49 a, astem 49 b and a resilient sleeve 49 c. The cylinder 49 a has an internalbore and is rotatably mounted at one end at the hinge axis 46. A firstend of the stem 49 b is slidingly received in the bore of the cylinder49 a. The opposite end of the stem 49 b is rotatably mounted to theU-shaped arm 47 at a third pivot point 51. The third pivot points 51 areunconnected to, and freely moveable relative to, the upper part 44 andlower part 43. The resilient sleeve 49 c is mounted externally on thestem 49 b and extends, in use, between abutment surfaces on the cylinder49 a and stem 49 b. The resilient sleeve 49 c accommodates shortening ofthe over-centre arm 49 but biases the over-centre arm 49 into anextended configuration. Movement of the third pivot points 51 towardsand away from the hinge axis 46 is thus possible by relative movement ofthe stems 49 b in the cylinders 49 a. The resilient sleeves 49 c arepreferably formed from silicone. Whilst the illustrated embodiment usestwo over-centre arms 49, it will be apparent that the closure mechanismmay be configured with only one over-centre arm 49.

The U-shaped arm 47 extends around the front of the holder 18 andcomprises two downwardly dependant hook members 52, one on each side ofthe holder 18, each comprising a cam surface facing the hinge axis 46.The fixed lower part 43 of the holder 18 is provided with two bosses 53,or detents, located one on each side of the lower part 43 at or near afront edge 54 thereof aligned generally with the hook members 52.

As shown in FIG. 4, the U-shaped arm 47 may be formed from a one pieceplastics moulding comprising an ergonomic hand grip and the hook members52 integral to the arm 47.

The cartridge mount 45 is rotatably mounted between the upper and lowerparts 43, 44 of the holder 18. The mount 45 is provided with asubstantially circular recess 55 which receives in use the beveragecartridge 100 (which is described in greater details below). The recess55 includes an irregularity 56 for accommodating the handle portion 24of the beverage cartridge 100 which also acts to prevent rotation of thebeverage cartridge 100 in the holder 18. The cartridge mount 45 issprung relative to the fixed lower part 43 such that in the openposition, as shown in FIG. 7, the cartridge mount 45 is biased out ofcontact with the fixed lower part 43 so that the cartridge mount 45 ismoved out of contact with the outlet and inlet piercer members 21, 22.The cartridge mount 45 is provided with an aperture 57 for receivingthere through the inlet and outlet piercers 21, 22 and a head of thecartridge recognition means 20 when the cartridge mount 45 is moved intothe closed position.

The upper part 44 comprises a generally circular body 58 housing acircular viewing window 59 through which a consumer can view thebeverage cartridge 100 during a dispense cycle and also visually confirmwhether a cartridge 100 is loaded in the machine 10. The viewing window59 is cup-shaped having a downwardly directed rim. In addition, theviewing window 59 is provided with a clamping member in the form of aninwardly directed tubular extension 61 as shown in FIG. 7. The extension61 is directed towards the lower part 43 and lies within the volume ofthe cartridge head when in the closed position as shown in FIG. 6. Theviewing window 59 is able to move axially relative to the housing 58 ofthe upper part 44. One arrangement of accomplishing the relativemovement is to provide a wave spring (not shown), or similar resilientmeans such as a rubberised ring, positioned between the viewing window59 and the circular housing 58. In an alternative arrangement, a seriesof helical compression springs (not shown) are provided extendingbetween the viewing window 59 and the housing 58. In both cases theresilient means allows the viewing window 59 to move axially relative tothe circular housing 58 by a small degree.

When the holder 18 is in the closed position, a distal end 62 of thetubular extension 61 of viewing window 59 bears against the clampingsurface 18 a of the beverage cartridge 100 biasing it against the lowerpart 43 as shown in FIG. 6 (in which the arrangement is illustratedcontaining a cartridge having a greater depth). The pressure exerted bythe tubular extension 61 on the outer member 102 ensures a fluid tightseal between the cartridge 100 and the holder 18. It should be notedthat the height of the viewing window 59, and hence also the cartridgehead 17, is such that cartridges 100 of various depths can be inserted.In FIG. 6 the arrangement is shown with a relative deep cartridge. Thesame cartridge head 17 can also accommodate shallower cartridges. Inthis case there will be a gap between the upper surface 11 of thecartridge 100 and the window 59. However the cartridge 100 is fullysealed at inlet and outlet by the pressure applied by the tubularextension 61.

The lower part 43 comprises the inlet and outlet piercers 21, 22 and thehead of the cartridge recognition means 20. The inlet piercer 21comprises a hollow needle-like tube 63 having a sharpened end 64 forperforating the laminate 108 of the beverage cartridge 100 in use. Theinlet piercer 21 is in fluid communication with a water conduit 65, asshown in FIG. 7, which passes through the lower part 43 and is connectedto an outlet conduit 66 of the water heater 13. The outlet piercer 22 issimilar in type to the outlet piercer described in the EP-A-0389141 andEP-A-0 334572 and comprises an open ended cylinder of circular orD-shaped cross-section having dimensions larger than the beveragedischarge spout 109. An arcuate portion 67 of the upper end of theoutlet piercer 22 is serrated to pierce and eventually cut the laminateof the beverage cartridge 100. The remainder of the upper end is cutback longitudinally of the cylinder at least to the base of the teeth 68of the serrated portion to fold or pull the cut laminate 108 away fromthe outlet aperture before the beverage is dispensed there through. Theoutlet piercer 22 pierces the laminate 105 externally of the dischargespout 143 and when the cartridge mount 45 is in the closed position,rests in the annulus between the discharge spout 143 and the outer wall42 of the discharge funnel 140. The outlet piercer 22 folds back the cutlaminate 105 into the annulus. Thereby both the outlet piercer 22 andthe cut laminate 105 are held out of the way of the discharged beverage.

The outlet piercer 22 is surrounded by a ledge which is raised relativeto its surroundings by 0.5 mm.

Advantageously, the outlet piercer 22 is removable from the lower part43 to enable it to be thoroughly cleaned, for example, in a dishwasher.The removable outlet piercer 22 is received in a recess in the lowerpart 43 where it is seated. The inlet piercer 21 and/or the outletpiercer 22 may be made of a metal, such as stainless steel, or from aplastics material. Advantageously, the use of plastic cutting elementsis enabled by use of a laminate 105 which is able to be punctured andcut by a non-metallic material. Consequently, the piercers 21, 22 can bemade less sharp which lowers the risk of injury to the consumer. Inaddition, plastic piercing elements are not prone to rust. Preferably,the inlet piercer 21 and the outlet piercer 24 are formed as a single,integral unit which is removable from the lower part 43.

In use, the upper part 44 of the holder 18 is movable from an openposition in which it is orientated vertically or towards the vertical asshown in FIG. 2, to a closed position in which it is orientatedsubstantially horizontally and in interengagement with the fixed lowerpart 43 and cartridge mount 45. The upper part 44 is moved from the opento the closed positions by operation of the clamping lever. To close theupper part 44 a user takes hold of the clamping lever by the U-shapedarm 47 and pulls downwards. Consequently, the upper part 44 rotateswhich first brings the tubular extension 61 of the viewing window 59into contact with the clamping surface 118 a of the beverage cartridge100. Continued rotation of the upper part 44 rotates the upper part 44and cartridge mount 45 down into contact with the lower part 43. Furtherrotation of the U-shaped arm 47 causes the U-shaped arm 47 to rotaterelative to the upper part 44 and the lower part 43 resulting in thehook members 52 of the upper part 44 engaging the bosses 53 of the lowerpart 43 with the cam surface riding over the bosses 53. During this laststage of rotation the cartridge 100 is compressed between the cartridgemount 45 and the viewing window 59. As a result, the viewing window 59is moved axially slightly relative to the circular housing 58 of theupper part 44 against the bias of the wave spring or helical springs.This movement allows for a take up of tolerances in the beveragecartridge 100 and beverage preparation machine 10 and ensures that theamount of compressive force applied to the cartridge 100 is kept withinan acceptable range. The clamping force of the mechanism as moderated bythe action of the wave spring or helical springs ensures a clampingpressure on the cartridge 100. It has been found that a force of between150N and 400N is required to counter the pressure in the cartridge 100.During closure of the cartridge head the laminate 105 of the cartridge100 is tensioned as it is brought into contact with the ledgesurrounding the outlet piercer 22 which causes the laminate 105 to flexout of plane as the distal end of the outer tube 42 of the cylindricalfunnel is moved upwardly by 0.5 mm relative to the flange 147. Thismovement also ensures that the great majority of the compressive forceapplied to the cartridge 100 acts through the central region of thecartridge 100 through the load-bearing inner member 103. These clampingforces help prevent failure of the cartridge 100 during pressurisationand also ensure that the inner member 103 and outer member 102 are fullyseated relative to one another and thus that all internal passagewaysand apertures remain at their intended dimensions even during internalpressurisation.

In the closed position, the separation of the distal end 62 of thetubular extension 61 and the lower part 43 is shown by reference D inFIG. 6. This distance is fixed by the dimensions of the viewing window59, housing 58 and lower part 43. The distance D is chosen to be thesame or marginally smaller than the distance d between the clampingsurface 118 a and laminate 105 under surface of the cartridges 100. Inthis way, on closure of the cartridge head 17 the cartridges 100 aresubjected to a fixed, known degree of compression. In addition, both thefirst and second embodiments of cartridge can be clamped with the samedegree of compression since distance D is the same for both cartridgetypes.

An imaginary datum line can be drawn between the first and second pivotpoints 48, 50 of the holder 18. As can be seen in FIG. 7, in the openposition the third pivot points 51 are located on the side of the datumline nearest the fixed lower part 43. As the upper part 44 reaches theclosed position, the third pivot points 51 of the clamping lever passthrough the datum line joining the first and second pivot points 48, 50to the opposite side of the line, furthest from the fixed lower part 43.Consequently, the U-shaped arm 47 ‘snaps through’ from a first stableposition to a second stable position. The snap through action isaccommodated by shortening of the over-centre arms 49 and consequentialcompression of the resilient sleeves 49 c. Once the third pivot points51 are past the imaginary datum line, the recovery of the resilientsleeves 49 c acts to continue the motion of the third pivot points 51away from the imaginary datum line. The clamping lever thus has abi-stable operation in that the lever is stable in the open or closedpositions but unstable at the point when the third pivot points 51 lieon the imaginary datum line joining the first and second pivot points48, 50. Thus, the snap-through action of the clamping lever provides apositive closure mechanism which leads to a definite closure actionwherein in the final stages of the clamping lever's rotation, thesnap-through action of the U-shaped arm 47 and second arms forces thehook members 52 firmly into engagement with the bosses 53. In addition,the resilient sleeves 49 c provide a resistance to re-opening of theupper part 44 since a minimum force is required to compress the sleeves49 c sufficiently to move the third pivot points 51 back into line withthe datum line joining the first and second pivot points 48, 50.Advantageously, the interengagement of the hook members 52 and thebosses 53 prevents separation of the upper and lower parts other than byrotation of the clamping lever. This is useful in preventing opening ofthe cartridge head 17 during operation when the cartridge head 17 issubject to internal pressurisation.

The pressure exerted by the upper section 44 ensures a full fluid tightseal between the cartridge 100 and the cartridge holder 18. The clampingforces help prevent failure of the cartridge 100 during pressurisationand also ensure that all of the internal passageways and apertureswithin the cartridge 100 remain at their intended dimensions even duringinternal pressurisation. To improve the seal with the cartridges 100 theapplicant has now found that lining the recess 55 of the cartridge mount45 with a rubber seal 55 a (see FIG. 7a ) improves the machine's abilityto withstand the significantly higher pressures generated during thebrewing cycle.

Control of the brew cycle is effected by the control processor of thebeverage preparation machine 10, which comprises a processing module anda memory. The control processor is operatively connected to, andcontrols operation of, the heater 13, pump 14, user interface 16, andother components described below.

The operational behaviour of the machine 10 is determined by softwareembedded in the control processor, for example as described inEP-A-1440644. The memory of the control processor includes one or morevariables for one or more operational parameters for the beveragepreparation machine 10. In the prior art machines these are generallythe temperature of the liquid passed through the beverage cartridge 100during the operating stage, the speed of charging the beverage cartridge100, the presence or otherwise of a soak step, the total dispensedvolume of the beverage, the flow rate of the liquid during the dischargestage, and the period of the purge stage.

One purpose of the cartridge recognition means 20 is, inter alia, toallow the machine 10 to recognise the type of beverage cartridge 100that has been inserted and to adjust one or more operational parametersaccordingly. The variables for the operational parameters are stored inthe memory. The cartridge 100 comprises a code 120 provided on or in thecartridge 100 representing the operational parameters required foroptimal dispensation of the beverage in that cartridge 100. An exampleof the code is described in EP-A-1440644.

The control processor memory further stores information on the type ofbeverage dispensed so that the operating cycle of the machine 10 may beadjusted for the next cartridge 100. This is especially advantageouswhere two or more beverage cartridges 100 are used sequentially to forma beverage. For example a coffee cartridge may be dispensed followed bya milk cartridge to form a cappuccino beverage. Alternatively achocolate cartridge could be used followed by a milk cartridge toproduce a creamy hot chocolate beverage. By using a memory that storesinformation on the first beverage dispensed, the manner of dispensingthe second cartridge, say a milk cartridge, may be altered to achieve anoptimum beverage. In the above example the milk dispensed for hotchocolate may, typically, be diluted less than the milk added to thecoffee. In addition, the milk dispensed for chocolate may be dispensedat a slower flow rate to lessen the degree of foaming of the beverage.Many combinations of cartridges are possible and operating parameters aswill be obvious to the skilled person. In addition, the memory may beused to allow the machine 10 to ‘predict’ the type of beverage that auser will next want to dispense. For example, if a user predominantlydrinks one beverage type then the machine can instruct the water heaterto remain at the optimum temperature for that beverage type.

Operation of the known prior art machines 10 comprises insertion of abeverage cartridge 100 into the cartridge head 17, carrying out adispense cycle in which the beverage is dispensed and removal of thecartridge 100 from the machine.

To insert the cartridge 100 the cartridge holder 18 is opened asdescribed above to expose the cartridge mount 45. The cartridge 100 isthen placed on the cartridge mount 45 received within the recess 46. Thecartridge holder 18 is then closed by operation of the clamping handle51 as described above. During closure the inlet and outlet piercerspierce the cartridge 100 to form the cartridge inlet 107 and outlet 108.

To commence the operating cycle the user operates the start/stop button28. The operating cycle comprises the steps of cartridge recognition andthe beverage preparation cycle.

Cartridge recognition is performed by the optical cartridge recognitionmeans 20 as described above assuming that the outputs from the cartridgesensor and lock sensor are satisfactory. Once the barcode 40 has beendecoded the operational parameters of the machine 10 are adjusted by thecontrol processor. The preparation cycle is then automaticallycommenced. The preparation cycle has four main stages, although not allof these are used for all beverage types:

-   -   1. Pre-wet    -   2. Pause    -   3. Brew stage    -   4. Purge

In the pre-wet stage the cartridge 100 is charged with liquid from thestorage tank 12 by means of the pump 14. The charging with water causesthe beverage ingredients 200 in the chamber 160 to be wetted. Thecharging may take place at a “fast” flow rate of 600 ml/min or a “slow”flow rate of 325 ml/min. The slow charging rate is particularly usefulfor cartridges 100 containing viscous liquid beverage ingredients wherethe ingredients require some dilution before they are able to be pumpedat a higher volume flow rate. The volume of liquid injected into thecartridge 100 is selected to ensure that liquid or beverage does notdrip out of the cartridge outlet 108 during this stage.

The pause stage allows the beverage ingredients 200 to soak in theliquid injected during the pre-wet stage for a predetermined period oftime. Both the pre-wetting and soaking stages are known to increase theyield of the extractibles from the beverage ingredients 200 and toimprove the end flavour of the beverage. Pre-wetting and soaking areparticularly used where the beverage ingredients are roast and groundcoffee.

In the brew stage liquid is passed through the cartridge 100 in order toproduce the beverage from the beverage ingredients 200. The temperatureof the liquid is determined by the control processor which sendsinstructions to the heater 13 to heat the liquid passing from the tank12 to the cartridge head 17. Liquid enters the cartridge holder 18 viaan inlet valve and the inlet piercer and then passes into the inletchamber 126 of the beverage cartridge 100. Brewing and/or mixing of thebeverage in the beverage cartridge 100 occurs, as described inEP-A-1440644, before the prepared beverage exits the cartridge outlet104, enters the outlet valve 37 and is directed into a suitably placedreceptacle in the dispensing station 27.

During the purge cycle the temperature of the water heater 13 is raisedsufficiently high to convert the water remaining in the system to steamand blowing the pressurised steam through the beverage preparationmachine 10 and the beverage cartridge 100. This ensures that allbeverage is dispensed and that the flow path is cleared ready fordispensing another beverage. The purge cycle may not commenceimmediately on cessation of the brew/mixing stage to allow for themajority of the fluid to clear the flow path.

Once the operating cycle has been completed, the machine automaticallystops and the consumer removes the cartridge 100 by opening thecartridge holder 18 and manually removing and disposing of the cartridge100. Alternatively, the machine 10 may be provided with an automaticejection mechanism for removing the cartridge automatically on openingthe cartridge holder 18.

The first of the significant improvements to the known beveragepreparation machines 10 referred to above is the provision of variablegeometry valve 60 (see FIGS. 9 to 15) provided adjacent the cartridgeoutlet 108 to provide post-cartridge pressure control. This enables themachine 10 to produce a wide variety of beverages, as it allows thecartridges 100 to be selectively brewed at either high or low pressureor a varying pressure during the brew cycle, depending on the type ofbrew cycle required for the beverage ingredients in the cartridge asidentified by the cartridge recognition means 20, thus providing anautomated variable pressure system. The modified machine is capable ofproducing beverages at a range of pressures, for example from 0 to 9bar, and more preferably from 0 to 6 bar.

The variable geometry valve 60 is positioned downstream of the cartridge100, and preferably positioned in the beverage outlet 37, which ispartially housed in, and extends from, the lower section 43 of thecartridge head 17 (see FIGS. 6 and 7). The valve 60 has at least an openand a restricted state, and more preferably all of the states identifiedbelow:—

-   -   1. Open (FIG. 11)    -   2. Restricted (FIG. 12)    -   3. Closed (FIG. 10)    -   4. Cleaning/purging.

Various types of valve may be used for the outlet valve 60, such as ballvalves, pinch valves, sleeve valves, seat valves or disc valves. Theembodiment illustrated in FIGS. 10 to 12 is a ball type valve which hasa rotating element 69 located in a chamber 70 in the beverage outlet 37.The rotating element 69 is rotatable between preset positions to providethe required states. The diameter of the bore of the valve 60 in theunrestricted position is preferably at least 5 mm which is required, forexample, for cartridges 100 providing low pressure filter beverages.

An alternative suitable valve is a pinch valve illustrated in FIGS. 13to 15 which comprises a flexible tube 71, preferably made of siliconrubber or an elastomeric material, and a clamping mechanism 72. In theunrestricted position (FIGS. 13a and 14) the beverage flows freelythrough the tube 71. The clamping mechanism 72 is activated to provide arestricted position (FIGS. 13b and 15) and closed position.

The valve 60 is controlled automatically by the control processor of themachine 10. Once the type of cartridge 100 inserted into the machine 10has been identified, by the decoding the barcode 40, the controlprocessor selects the correct initial setting and, if appropriate, anysubsequent operation of the valve 60 for the relevant beverage type.

The machine 10 can operate in a range of modes, with the valve 60 in oneor more positions, some examples of which are:—

1. Valve Open Throughout the Brewing Cycle

When the valve 60 is in its open position the operating pressure isbelow 2 bar allowing a steady state through flow rate of up to 400ml/min. The beverage is dispensed under similar conditions to thosedescribed in EP-A-1440644. This mode is particularly useful as itrenders the machine 10 backwardly compatible with existing cartridgesfor preparing low pressure beverages, such as tea, foamed milk orchocolate.

2. Valve Restricted Throughout the Brewing Cycle

When the valve 60 is in its restricted position it creates a relativelyhigh back pressure within the cartridge 100, which results in anoperating pressure of up to 4, 6 or even 9 bar and provides a steadystate through flow rate of 60 to 300 ml/min. This is sufficient toobtain the necessary solids extraction and emulsification of oils in thebeverage ingredients 200 for an espresso beverage. The consequentialrestriction in the beverage outlet 37 provides a shearing and mixingaction in the beverage flowing through the valve 60, giving rise to goodair/liquid emulsification and resulting in an improved crema. This modecan advantageously be used for preparing higher pressure beverages, suchas espressos and cappuccinos, from cartridges 100 which do not havemeans for entraining air to effect the mixing action, i.e. so callednon-eductor cartridges.

3. Valve Closed then Restricted

If the valve 60 is closed immediately at the start of the brewing cycle(before the pump 14 commences and during the pre-wet cycle), thisenables a higher pressure to be developed within the cartridge 100 thanwhen the valve 60 is in it's restricted position.

Further combinations may be appropriate, such as valve closed then openor valve closed then restricted then open according to the desiredeffect to be achieved.

If required, the valve 60 can be pulsed between various positions duringthe brewing cycle, or a part thereof. This manner of valve operationduring the delivery cycle enables beverages with a crema having agraduated colour and/or bubble size to be produced.

During the purge cycle the valve 60 is controlled by the controlprocessor to divert the steam to a drain area rather than to thedispensing station 27 to preserve the appearance of the beverage andprevent contamination.

The second of the significant improvements to the known beveragepreparation machines 10 referred to above is the addition to the brewcontrol system of gas management. Surprisingly the applicant has nowdiscovered that the characteristics of beverages prepared in this typeof beverage preparation machine 10 can be modified beyond boundarieshereto seen in prior art machines. The surprising effect is enacted bycontrolling the volume of gas in the delivery system during thepreparation of the beverage to prescribe the amount of high qualitycrema resulting in a controlled amount of crema on a beverage varyingfrom a delicate layer up to a surprisingly deep layer in the finalbeverage. The applicant has found a way to successfully use gases withinthe beverage preparation machine to modify the gas:liquid ratio toproduce a surprising volume of good stable crema in prepared beveragesnever seen before in prior art machines. Maintaining a greater volume ofgas resident in the delivery system enables a much larger gas:liquidratio to be achieved during brewing and dispensing and this produces acorrespondingly larger volume of crema. Decreasing the volume of gasenables the ratio to be decreased to reduce the crema volume. The bubblesize is also influenced by the gas:liquid ratio, so a lower ratio can beused to provide a tight and creamy crema and a higher ratio used toprovide a more loose and bubbly crema. This improvement thereforeprovides the ability to optimise the crema volume and bubble size foreach beverage dispensed. It has been found that by manipulating the gasgood quality espressos can be brewed with a crema volume greater than25% of the beverage volume whilst minimising the occurrence of bubbleshaving a diameter of more than 172 microns which is not previously seento be possible in known beverage preparation machines of this type.

The improvement is achieved by adapting the control of the brew cycle toprovide means for managing the volume of gas within the delivery systemwhich conveys the water from the tank 12 to the beverage ingredients 200and to the dispensing outlet. All further references in thisspecification to the delivery system are intended to include anypredetermined section thereof, for example the section extending fromthe water heater 13 to the cartridge 100 and may also include, ifrelevant, some gas contained within a headspace of the cartridge 100.

The “basic volume” of gas which can reside within the delivery system ofany given machine 10 is dependant on its construction. The “actualvolume” at any given time will vary according to whether the machine 10has just been used to prepare a beverage, what type of beverage it wasused for and whether a steam purge cycle has been run. Thus the improvedbrew cycle control incorporates means for varying the volume of gas inthe delivery system according to the type of beverage to be dispensed(i.e. one requiring a crema with smaller and fewer bubbles or one whichrequires a greater froth of larger bubbles) taking into account theactual volume of gas already present. The means for varying the volumeof gas may be achieved by combinations of:—

-   -   1. purging the delivery system after a brewing cycle is        complete, and prior to a subsequent high pressure brew, which        will increase the gas:liquid ratio;    -   2. venting gas from the delivery system prior to high pressure        brewing, which will decrease the gas:liquid ratio; and    -   3. inducting gas into the delivery system prior to high pressure        brewing, which will increase the gas:liquid ratio.

Valve means are preferably provided to enable the volume of gas withinthe delivery system to be reduced and an air pump to enable gas(typically air) to be injected into the system. A separate, dedicatedair valve may be incorporated in the delivery system, either upstream ordownstream of the cartridge 100. Preferably the variable geometry valve60 described above may be used as the valve means.

To enable this improved brew cycle control to be effected, additionalparameters to those described in connection with the basic machine 10may be stored in the memory of the control processor. These additionalparameters include the basic volume of gas for the specific constructionof machine 10 (which will apply to the machine 10 which is unused orafter it has been purged) and the volume required during high pressurebrewing for optimising the crema for each specific beverage. Preferablythe additional parameters also include the actual volume of gas whichwill remain in the delivery system after each type of brew operationwhich the machine 10 is capable of. However this is not wholly necessaryif the machine 10 is programmed to run a steam purge cycle after everybeverage is dispensed, which effectively resets the actual volume to thebasic volume, because it flushes the dispensing system downstream of thewater heater 13 of any remaining liquid.

The brew cycle will therefore include an additional step, namely a gasadjustment cycle before the pre-wet cycle. The gas adjustment cycle thusincludes:—

1. An assessment of the required volume of gas for the type of beverageto be prepared. This will most conveniently be the selection from theprocessor memory of the required parameter associated with the cartridgecode 120;

2. The determination of the actual volume of gas currently resident inthe delivery means according to the last operation of the machine 10.This will be the basic volume for an unused machine or if a purge cyclehas been run. If the machine has just been used to prepare a beverageand no purge cycle run, the processor ideally selects from the memorythe parameter for the remaining gas according to the last beverage.Alternatively, means may also be provided to specifically monitor thevolume of gas within the delivery system at any point in time;

3. A calculation of the volume of gas to be inducted into or vented fromthe delivery system to achieve the required volume;

4. The modification of the volume of gas, if required, by the inductionof additional gas (typically air) or the venting of excess gas.

In one example the beverage preparation machine 10 has a basic volume ofgas of 36 ml in the section of the delivery means extending between thewater heater 13 and the beverage ingredients 200.

There are a number of different modes of operation for step 4 dependingon the outcome of step 3, depending on what type of valve means areused. If the valve means are downstream of the cartridge, i.e. an outletvalve, one way of controlling the volume of air upstream of the beverageingredients 200 prior to high pressure brewing is by closing the outletvalve at different points in the brew cycle as follows:—

1. The Correct Volume of Gas is Present

If the processor calculates that it requires the full basic volume ofgas (36 ml) for the beverage to be dispensed, as determined from thereading of the code 120, it closes the outlet valve at the start of thebrew cycle, before any water flows from the water heater 13. This meansthat the compression of gas in the delivery system will commenceimmediately and the cartridge 100 will be subject to higher pressuresduring the pre-wet and soak cycles, with the valve only opening todispense the resultant beverage. As the outlet valve is closed beforethe pump 14 is started, all of the 36 ml of trapped gas is mixed in tothe resulting beverage and a larger volume of slightly coarser crema isobtained (FIG. 16a ). In the example shown the volume of crema Y in agraduated glass, flat bottomed beaker was 20 ml compared to the volumeof liquid X, which was 50 ml.

The chart shown in FIG. 16b represents an example of brew cycleparameters used to produce a beverage in this mode with a large volumeof crema under test conditions.

In this chart, a stop condition of 0 seconds (e.g. against the removegas step) indicates that the step is not carried out.

2. Too Much Gas is Present

If, on the other hand, a beverage with a small volume of crema isindicated by the cartridge 100 inserted and there is an excess of gaspresent in the system, the outlet valve is closed after the pump 14 hasoperated for a short time until the excess gas in the delivery systemhas escaped through the open valve at low pressure. With the valve beingclosed later in the brew cycle, the required volume of gas is vented toatmosphere via the cartridge 100 and valve, so a smaller quantity oftrapped gas is left to be compressed and mixed in to the resultingbeverage during high pressure brewing and consequently a smaller volumeof finer crema is obtained (FIG. 17a ). In the example shown the volumeof crema Y in a graduated glass, flat bottomed beaker was 5 ml comparedto the volume of liquid X, which was 50 ml.

The chart shown in FIG. 17b represents an example of brew parametersused to produce a beverage in this mode with a small volume of cremaunder test conditions.

3. Insufficient Gas Present

If step 3 indicates that more gas needs to be inducted, the outlet valveis closed immediately and the air pump operated until the deficit hasbeen made up. Thereafter high pressure brewing commences.

The graph of FIG. 31 is a digital image analysis showing a comparison ofthe crema characteristics produced by the present beverage preparationmachine 10 (machine A) utilising the gas management system and two priorart machines (machines B and C) without such gas management system.Comparing the profiles for each machine from the peak (^(˜)172 μmdiameter) rightwards (increasing bubble size), it can be seen thatmachine A exhibits a very tight distribution of small bubbles within thecrema. Machine C (the Nespresso Latissma™ which is a high pressuremachine which has a pressure rating of around 19 bar and operates at apressure between 9 and 15 bar) produces a broader/coarser distributionwith a number of larger diameter bubbles, whilst machine B (theapplicant's own Tassimo/Bosch Machine™ similar to that described inEP-A-1440644 which is a low pressure machine operating at pressuresbelow 2 bar) is coarser still, though without the larger bubbles seenfor machine C.

The tail to the left of the chart (extremely small bubbles) ischaracteristic of the limits of the image analysis systems used toproduce the graph, though is qualitatively similar.

Some elements of the control of the gas in the beverage machine 10 mayalso be effected manually by the use of suitable buttons for the user topress, to indicate the type of beverage being produced and the requiredcrema characteristics.

Whilst this improvement has been described with reference to beveragemachines 10 which use cartridges 100, it may also be used in bulkbrewers and other non-cartridge machines.

Embodiments of cartridges 100 which are suitable for use in the machine10 having the improvements described above are shown in FIGS. 18 to 30.

The cartridge 100 generally comprises an outer member 102, an innermember 103 and a laminate 105. The outer member 102, inner member 103and laminate 105 are assembled to form the cartridge 100 which has aninterior 106 for containing one or more beverage ingredients, an inlet107, an outlet 108 and a beverage flow path linking the inlet 107 to theoutlet 108 and which passes through the interior 106. The inlet 107 andoutlet 108 are initially sealed by the laminate 105 and are opened inuse by piercing or cutting of the laminate 105. The beverage flow pathis defined by spatial inter-relationships between the outer member 102,inner member 103 and laminate 105 as discussed below. Other componentsmay optionally be included in the cartridge 100, such as a filter 104,as will be described further below.

A first version of cartridge 100 which will be described is shown inFIGS. 19 to 29. The first version of the cartridge 100 is particularlydesigned for use in dispensing espresso-style products such as roast andground coffee where it is desirable to produce a crema. However, thisversion of the cartridge 100 may be used with other products such aschocolate, coffee, tea, sweeteners, cordials, flavourings, alcoholicbeverages, flavoured milk, fruit juices, squashes, sauces and desserts.

As can be seen from FIG. 23, the overall shape of the cartridge 100 isgenerally circular or disc-shaped with the diameter of the cartridge 100being significantly greater than its height. A major axis X passesthrough the centre of the outer member as shown in FIG. 19. Typicallythe overall diameter of the outer member 102 is 74.5 mm±6 mm and theoverall height is 16 mm±3 mm. Typically the volume of the cartridge 100when assembled is 30.2 ml±20%.

The outer member 102 generally comprises a bowl-shaped shell 110 havinga curved annular wall 113, a closed top 111 and an open bottom 112. Thediameter of the outer member 102 is smaller at the top 111 compared tothe diameter at the bottom 112, resulting from a flaring of the annularwall 113 as one traverses from the closed top 111 to the open bottom112. The annular wall 113 and closed bottom 112 together define areceptacle having an interior 134.

A hollow inwardly directed cylindrical extension 118 is provided in theclosed top 111 centred on the major axis X. As more clearly shown inFIG. 20, the cylindrical extension 18 comprises a stepped profile havingfirst, second and third portions 119, 120 and 121. The first portion 119is right circular cylindrical. The second portion 120 is frusto-conicalin shape and is inwardly tapered. The third portion 121 is another rightcircular cylinder and is closed off by a lower face 131. The diameter ofthe first, second and third portion 119, 120 and 121 incrementallydecreases such that the diameter of the cylindrical extension 118decreases as one traverses from the top 111 to the closed lower face 131of the cylindrical extension 118. A generally horizontal shoulder 132 isformed on the cylindrical extension 118 at the junction between thesecond and third portions 120 and 121.

An outwardly extending shoulder 133 is formed in the outer member 102towards the bottom 112. The outwardly extending shoulder 133 forms asecondary wall 115 co-axial with the annular wall 113 so as to define anannular track forming a manifold 116 between the secondary wall 115 andthe annular wall 113. The manifold 116 passes around the circumferenceof the outer member 102. A series of slots 117 are provided in theannular wall 113 level with the manifold 116 to provide gas and liquidcommunication between the manifold 116 and the interior 134 of the outermember 102. As shown in FIG. 21, the slots 117 comprise vertical slitsin the annular wall 113. Between twenty and forty slots are provided. Inthe embodiment shown thirty-seven slots 117 are provided generallyequi-spaced around the circumference of the manifold 16. The slots 117are preferably between 1.4 and 1.8 mm in length. Typically the length ofeach slot 117 is 1.6 mm representing 10% of the overall height of theouter member 102. The width of each slot 117 is between 0.25 and 0.35mm. Typically, the width of each slot 117 is 0.3 mm. The width of theslots 117 is sufficiently narrow to prevent the beverage ingredientspassing there through into the manifold 116 either during storage or inuse.

An inlet chamber 126 is formed in the outer member 102 at the peripheryof the outer member 102. A cylindrical wall 127 is provided, as mostclearly shown in FIG. 23, which defines the inlet chamber 126 within,and partitions the inlet chamber 126 from, the interior 134 of the outermember 102. The cylindrical wall 127 has a closed upper face 128 whichis formed on a plane perpendicular to the major axis X and an open lowerend 129 co-planar with the bottom 12 of the outer member 102. The inletchamber 26 communicates with the manifold 116 via two slots 130 as shownin FIG. 19. Alternatively, between one and four slots may be used tocommunicate between the manifold 116 and the inlet chamber 126.

A lower end of the outwardly extending shoulder 133 is provided with anoutwardly extending flange 135 which extends perpendicularly to themajor axis X. Typically the flange 135 has a width of between 2 and 4mm. A portion of the flange 135 is enlarged to form a handle 124 bywhich the outer member 102 may be held. The handle 124 is provided withan upturned rim 125 to improve grip.

The outer member 102 is formed as a single integral piece from highdensity polyethylene, polypropylene, polystyrene, polyester, or alaminate of two or more of these materials. A suitable polypropylene isthe range of polymers available from DSM UK Limited (Redditch, UnitedKingdom). The outer member may be opaque, transparent or translucent.The manufacturing process may be injection moulding.

The inner member 103 as shown in FIGS. 25 to 28, comprises an annularframe 141 and a downwardly extending cylindrical funnel 140. A majoraxis X passes through the centre of the inner member 103 as shown inFIG. 25.

As best shown in FIGS. 26 and 27, the annular frame 141 comprises anouter rim 151 and an inner hub 152 joined by ten equi-spaced radialspokes 153. The inner hub 152 is integral with and extends from thecylindrical funnel 140. Filtration apertures 155 are formed in theannular frame 141 between the radial spokes 153. A filter 104 isdisposed on the annular frame 141 so as to cover the filtrationapertures 155. The filter is preferably made from a material with a highwet strength, for example a non-woven fibre material of polyester. Othermaterials which may be used include a water-impermeable cellulosicmaterial, such as a cellulosic material comprising woven paper fibres.The woven paper fibres may be admixed with fibres of polypropylene,polyvinyl chloride and/or polyethylene. The incorporation of theseplastic materials into the cellulosic material renders the cellulosicmaterial heat-sealable. The filter 104 may also be treated or coatedwith a material which is activated by heat and/or pressure so that itcan be sealed to the annular frame 141 in this way.

As shown in the cross-sectional profile of FIG. 25, the inner hub 152 islocated at a lower position than the outer rim 151, resulting in theannular frame 141 having a sloping lower profile.

The upper surface of each spoke 153 is provided with an upstanding web154 which divides a void space above the annular frame 141 into aplurality of passages 157. Each passage 157 is bounded on either side bya web 154 and on a lower face by the filter 104. The passages 157 extendfrom the outer rim 151 downwardly towards, and open into, thecylindrical funnel 140 at openings 156 defined by the inner extremitiesof the webs 154.

The cylindrical funnel 140 comprises an outer tube 142 surrounding aninner discharge spout 143. The outer tube 142 forms the exterior of thecylindrical funnel 140. The discharge spout 143 is joined to the outertube 142 at an upper end of the discharge spout 143 by means of anannular flange 147. The discharge spout 143 comprises an inlet 145 at anupper end which communicates with the openings 156 of the passages 157and an outlet 144 at a lower end through which the prepared beverage isdischarged into a cup or other receptacle. The profile of the dischargespout 43 comprises a stepped profile with a distinct dog-leg 166 near anupper end of the tube 143.

As shown in FIG. 25, the discharge spout 143 is provided with apartition 165 which extends part way up the discharge spout 143 from theoutlet 144. The partition 165 helps to prevent the beverage sprayingand/or splashing as it exits the discharge spout 143.

A rim 167 is provided upstanding from the annular flange 147 joining theouter tube 142 to the discharge spout 143. The rim 167 surrounds theinlet 145 to the discharge spout 143 and defines an annular channel 169between the rim 167 and the upper portion of the outer tube 142. The rim167 is provided with an inwardly directed shoulder 168. At one pointaround the circumference of the rim 167 an aperture 170 is provided inthe form of a slot which extends from an upper edge of rim 167 to apoint marginally below the level of the shoulder 168 as most clearlyshown in FIGS. 25 and 25 a. The slot has a width of 0.64 mm.

An air inlet 171 is provided in annular flange 147 circumferentiallyaligned with the aperture 170 as shown in FIGS. 28 and 28 a. The airinlet 171 comprises an aperture passing through the flange 147 so as toprovide communication between a point above the flange 147 and the voidspace below the flange 147 between the outer tube 142 and dischargespout 143. Preferably, and as shown, the air inlet 171 comprises anupper frusto-conical portion 173 and a lower cylindrical portion 172.The air inlet 171 is typically formed by a mould tool such as a pin. Thetapered profile of the air inlet 171 allows the mould tool to be moreeasily removed from the moulded component. The wall of the outer tube142 in the vicinity of the air inlet 171 is shaped to form a chuteleading from the air inlet 171 to the inlet 145 of the discharge spout143. As shown in FIG. 28a , a canted shoulder 174 is formed between theair inlet 171 and the chute to ensure that the jet of beverage issuingfrom the slot 170 does not immediately foul on the upper surface of theflange 147 in the immediate vicinity of the air inlet 171.

The inner member 103 may be formed as a single integral piece frompolypropylene or a similar material as described above and by injectionmoulding in the same manner as the outer member 102.

Alternatively, the inner member 103 and/or the outer member 102 may bemade from a biodegradable polymer. Examples of suitable materialsinclude degradable polyethylene (for example, SPITEK supplied bySymphony Environmental, Borehamwood, United Kingdom), biodegradablepolyester amide (for example, BAK 1095 supplied by SymphonyEnvironmental), poly lactic acids (PLA supplied by Cargil, Minnesota,USA), starch-based polymers, cellulose derivatives and polypeptides.

The laminate 105 is formed from two layers, a first layer of aluminiumand a second layer of cast polypropylene. The aluminium layer is between0.02 and 0.07 mm in thickness. The cast polypropylene layer is between0.025 and 0.065 mm in thickness. In one embodiment the aluminium layeris 0.06 mm and the polypropylene layer is 0.025 mm thick. This laminate105 is particularly advantageous as it has a high resistance to curlingduring assembly. As a result the laminate 105 may be pre-cut to thecorrect size and shape and subsequently transferred to the assemblystation on the production line without undergoing distortion.Consequently, the laminate 108 is particularly well suited to welding.Other laminate materials may be used including PET/Aluminium/PP,PE/EVOH/PP, PET/metallised/PP and Aluminium/PP laminates. Roll laminatestock may be used instead of die cut stock.

The cartridge 100 may be closed by a rigid or semi-rigid lid instead ofa flexible laminate 105.

Assembly of the cartridge 100 involves the following steps:

-   -   a) the inner member 103 is inserted into the outer member 102;    -   b) the filter 104 is cut to shape and placed onto the inner        member 103 so to be received over the cylindrical funnel 140 and        come to rest against the annular frame 141;    -   c) the inner member 103, outer member 102 and filter 104 are        joined by ultrasonic welding;    -   d) the cartridge 100 is filled with one or more beverage        ingredients;    -   e) the laminate 105 is affixed to the outer member 102.

These steps will be discussed in greater detail below.

The outer member 103 is orientated with the open bottom 112 directedupwards. The inner member 103 is then inserted into the outer member 102with the outer rim 151 being received as a loose fit in an axialextension 114 at top 111 of the cartridge 100. The cylindrical extension118 of the outer member 102 is at the same time received in the upperportion of the cylindrical funnel 140 of the inner member 103.

The third portion 121 of the cylindrical extension 118 is seated insidethe support rim 167. The shoulder 132 of the cylindrical extension 118between the second portion 120 and third portion 121 bears against theupper edge of the support rim 167 of the inner member 103. An interfacezone is thus formed between the inner member 103 and the outer member102 comprising a face seal between the cylindrical extension 118 and thesupport rim 167 which extends around nearly the whole circumference ofthe cartridge 100. The seal between the cylindrical extension 118 andthe support rim 167 is not fluid-tight though since the slot 170 in thesupport rim 167 extends through the support rim 167 and downwardly to apoint marginally below the shoulder 168. Consequently the interface fitbetween the cylindrical extension 118 and the support rim 167 transformsthe slot 170 into an aperture providing gas and liquid communicationbetween the annular channel 169 and the discharge spout 143. Theaperture is typically 0.64 mm wide by 0.69 mm long.

The filter 104 is then placed over the inner member 103 such that thefilter material contacts the annular rim 151. An ultrasonic weldingprocess is then used to join the filter 104 to the inner member 103 andat the same time, and in the same process step, the inner member 103 tothe outer member 102. The inner member 103 and filter 104 are weldedaround the outer rim 151. The inner member 103 and outer member 102 arejoined by means of weld lines around the outer rim 151 and also theupper edges of the webs 154.

As shown most clearly in FIG. 29, the outer member 102 and inner member103 when joined together define a void space in the interior 106 belowthe annular flange 141 and exterior the cylindrical funnel 140 whichforms a filtration chamber. The filtration chamber 160 and passages 157above the annular frame 141 are separated by the filter paper 104.

The filtration chamber 160 contains the one or more beverage ingredients200. The one or more beverage ingredients 200 are packed into thefiltration chamber 160. For an espresso-style beverage the ingredient istypically roast and ground coffee. The density of packing of thebeverage ingredients in the filtration chamber 130 can be varied asdesired. Typically, for a filtered coffee product the filtration chambercontains between 5.0 and 10.2 grams of roast and ground coffee in afiltration bed of thickness of typically 5 to 14 mm. Optionally, theinterior 106 may contain one or more bodies, such as spheres, which arefreely movable within the interior 106 to aid mixing by inducingturbulence and breaking down deposits of beverage ingredients duringdischarge of the beverage.

The laminate 105 is then affixed to the outer member 102 by forming aweld 161 around the periphery of the laminate 105 to join the laminate105 to the lower surface of the outwardly extending flange 135. The weld161 is extended to seal the laminate 105 against the lower edge of thecylindrical wall 127 of the inlet chamber 126. Further, a weld 162 isformed between the laminate 105 and the lower edge of the outer tube 142of the cylindrical funnel 140. The laminate 105 forms the lower wall ofthe filtration chamber 160 and also seals the inlet chamber 126 andcylindrical funnel 140. However, a small gap 163 exists prior todispensation between the laminate 105 and the lower edge of thedischarge spout 43. A variety of welding methods may be used, such asheat and ultrasonic welding, depending on the material characteristicsof the laminate 105.

Advantageously, the inner member 103 spans between the outer member 102and the laminate 105. The inner member 103 is formed from a material ofrelative rigidity, such as polypropylene. As such, the inner member 103forms a load-bearing member that acts to keep the laminate 105 and outermember 102 spaced apart when the cartridge 100 is compressed. It ispreferred that the cartridge 100 is subjected to a compressive load ofbetween 130 and 280N in use. The compressive force acts to prevent thecartridge failing under internal pressurisation and also serves tosqueeze the inner member 103 and outer member 102 together. This ensuresthat the internal dimensions of passageways and apertures in thecartridge 100 are fixed and unable to change during pressurisation ofthe cartridge 100.

In use the water, under pressure, enters the cartridge 100 through theinlet 107 into the inlet chamber 126. From there the water is directedto flow through the slots 117 and round the manifold 116 and into thefiltration chamber 160 of the cartridge 1 through the plurality of slots117. The water is forced radially inwardly through the filtrationchamber 160 and mixes with the beverage ingredients 200 containedtherein. The water is at the same time forced upwardly through thebeverage ingredients 200. The beverage formed by passage of the waterthrough the beverage ingredients 200 passes through the filter 104 andfiltration apertures 155 into the passages 157 lying above the annularframe 141.

Beverage in the radial passages 157 flows downwardly along the passages157 formed between the webs 154 and through the openings 156 and intothe annular channel 169 of the cylindrical funnel 140. From the annularchannel 169 the beverage is forced under pressure through the aperture128 by the back pressure of beverage collecting in the filtrationchamber 160 and passages 157. The beverage is thus forced throughaperture as a jet and into an expansion chamber formed by the upper endof the discharge spout 143. As shown in FIG. 29, the jet of beveragepasses directly over the air inlet 171. Passage of the beverage throughthe restriction of the aperture causes the pressure of the beverage tobe reduced. As the beverage enters the discharge spout 143 the pressureof the beverage is still relatively low. As a result air is entrainedinto the beverage stream in the form of a multitude of small air bubblesas the air is drawn up through the air inlet 171. The jet of beverageissuing from the aperture is funneled downwards to the outlet 144 wherethe beverage is discharged into a receptacle such as a cup where the airbubbles form the desired crema. Thus, the aperture and the air inlet 171together form an eductor which acts to entrain air into the beverage.Flow of beverage into the eductor should be kept as smooth as possibleto reduce pressure losses. It should be noted that, in the high pressurestate, the air eduction mechanism is de-activated.

The sealing of the filter 104 onto the spokes 153 and the welding of therim 151 with the outer member 102 ensures that there are noshort-circuits and all the beverage has to pass through the filter 104.

FIG. 30 shows a second embodiment of beverage cartridge 100 which can beused in the beverage preparation machine 10 of the present invention.Like components between the first and second embodiments have beenreferenced with like numerals. Many of the components and functions ofthe second embodiment of cartridge 100 are the same as for the firstembodiment. However, it can be seen from FIG. 30 that the cartridge 100has a greater overall height compared to the cartridge 100 shown in FIG.29. The outer member 102 is taller and thereby defines a larger voidspace in which a larger quantity of beverage ingredients 200 can bestored. The second embodiment of cartridge 100 is therefore suitable fordispensing larger volumes of beverage. The diameter of the outer member102 and cartridge 100 are the same as in the first embodiment. Typicallythe storage volume of the cartridge 100 when assembled is 50 to 58ml±20%. As with the first embodiment, the upper surface of the outermember 102 is provided with a recess having a clamping surface 118located at a bottom thereof. According to the present invention, theseparation D between surface 118 a and the underside of the laminate 105is the same as for the first embodiment. As a result, the elongatedrecess extends approximately 60% of the distance towards the laminate105. This advantageously allows for a simplified clamping arrangement tobe used as described below.

Also, the second embodiment of cartridge 100 lacks an eductor air inlet171.

The first and second embodiments of cartridge 1 described above aregiven as examples of an “eductor” type of cartridge and a “non-eductor”type cartridge which may be used with the improved beverage preparationmachine described above.

The invention claimed is:
 1. A method of preparing beverages using abeverage preparation machine for preparing beverages from one or morebeverage ingredients, said beverage preparation machine comprising acartridge head for receiving, in use, a cartridge containing said one ormore beverage ingredients, a delivery system for supplying liquid from astorage tank to the cartridge head, valve means and a pump for supplyingliquid through the delivery system, the method comprising the step ofcontrolling a volume of air resident in a part of the delivery system ofthe machine to produce predetermined crema or froth characteristics in aprepared beverage, wherein the volume of air is actively controlled bydecreasing the volume of air to decrease the air:liquid ratio in thebeverage produced, or by maintaining the volume of air, and the controlis effected in the following manner:
 1. if the required volume of air ispresent, closing the valve means and subsequently starting operation ofthe pump; or
 2. if too much air is present, opening the valve means,starting operation of the pump to vent air from the delivery system, andsubsequently closing the valve means.
 2. A method of preparing beveragesas claimed in claim 1 in which the volume of air in the delivery systemis further controlled by purging the delivery system.
 3. A method ofpreparing beverages as claimed in claim 1 further comprising the step ofmeasuring the volume of air resident in the delivery system.
 4. A methodof preparing beverages as claimed in claim 1 in which the volume of airresident in the delivery system is initially determined from storedparameters according to a last operation of the machine, said storedparameters comprising a basic volume parameter stored in the controlmeans which is the volume of air which resides in the delivery system ofan unused machine or a machine after a purging cycle has been run.
 5. Amethod of preparing beverages as claimed in claim 1 in which the volumeof air is controlled automatically according to the type of beveragebeing produced.
 6. A method of preparing beverages as claimed in claim 1in which the control of the volume of air is effected manually.
 7. Amethod of preparing beverages as claimed in claim 1 in which the controlof the volume of air is effected upstream of the beverage ingredients.8. A method of preparing beverages as claimed in claim 1 in which thecontrol of the volume of air is effected downstream of the beverageingredients.
 9. A method of preparing beverages as claimed in claim 1 inwhich the volume of air is controlled by selectively opening and/orclosing valve means in the delivery system prior to and/or duringbeverage preparation.
 10. A method of preparing beverages as claimed inclaim 1 in which an actual volume of air resident in the delivery systemis determined from stored parameters relating to a volume of airremaining in the delivery system after a last operation of the machine,said stored parameters comprising parameters relating to the actualvolume of air remaining in the delivery system after each type ofbeverage which the machine is programmed to prepare.
 11. A method ofpreparing beverages as claimed in claim 1 in which the valve means andpump means are automatically controlled by a control processor.
 12. Amethod of preparing beverages as claimed in claim 1, wherein the valvemeans are disposed downstream of the cartridge-receiving part of thecartridge head.